Citation

Brazen DM, Todd MK, Ambegaonkar JP, Wunderlich R, Peterson C. Clin. J. Sport. Med. 2010; 20(4): 286-292.

Affiliation

School of Kinesiology and Recreation Studies, James Madison University, Harrisonburg, Virginia; daggerSports Medicine Assessment Research and Testing Laboratory, School of Recreation, Health, and Tourism, George Mason University, Manassas, Virginia; and Departments of Biology; and Health Sciences, James Madison University, Harrisonburg, Virginia.

Copyright

(Copyright © 2010, Canadian Academy of Sport Medicine, Publisher Lippincott Williams and Wilkins)

DOI

10.1097/JSM.0b013e3181e8f7dc

PMID

20606514

Abstract

OBJECTIVE: To examine the effects of fatigue on landing biomechanics in single-leg drop landings. DESIGN:: Quasi-experimental. SETTING:: Controlled research laboratory. PARTICIPANTS:: Twenty-four healthy individuals (12 women and 12 men). INTERVENTIONS:: Participants performed 3 single-leg drop landings from a height of 0.36 m before and after a fatiguing protocol. MAIN OUTCOME MEASURES:: Sagittal ankle flexion, sagittal knee flexion, and frontal knee valgus angles (degrees) at initial ground contact; vertical ground reaction forces (N); and time to stabilization (TTS) were compared between sexes and before (pre) and after (post) the fatiguing protocol. RESULTS:: After fatigue, participants landed with greater knee flexion P = 0.001; pre 142.58 (14.35) degrees; post 136.12 (14.48) degrees and ankle plantar flexion P = 0.012; pre 79.04 (6.96) degrees; post 80.78 (6.13) degrees, and higher peak vertical ground reaction forces (P = 0.002; pre 2202.5 (536.29) N to post 2537.86 (469.66) N but did not show changes in frontal knee angles P = 0.815; pre, 7.94 (3.74) degrees; post, 8.08 (4.33) degrees. Participants had higher anterior-posterior TTS P = 0.021; pre 1.73 (0.53) seconds to post 1.93 (0.53) seconds and vertical TTS P = 0.002; pre 0.65 (0.24) seconds to post 0.93 (0.37) seconds with a significant interaction noted in medial-lateral TTS P = 0.043; pre 1.49 (0.64) seconds to post 1.61 (0.67) seconds. No significant sex differences existed across any of the examined variables. CONCLUSIONS:: When landing after fatigue, participants had greater knee and ankle flexion angles at initial contact, had greater peak ground reaction forces, and required longer times to stabilize the body after landing, regardless of sex. Overall, fatigue clearly affects lower body biomechanics during single-leg landings. Whether these changes actually increase injury risk during activity warrants further investigation.

Language: en